1. Field of the Invention
This invention relates to a device for measuring the characteristics of microwave components in the form of chips or discrete packages of integrated circuits and hybrid circuits. This device serves to measure the parameters related to scattering, noise or output power within the range of 2 to 40 GHz.
2. Description of the Prior Art
Any microwave component, whether in the form of a chip of semiconductor material, or in the form of a discrete component (transistor, for example), of an integrated circuit component (amplifier, for example) encapsulated in a package, or in the form of a hybrid circuit mounted on a substrate, must be defined in accordance with predetermined parameters before being put to use. It is a common practice to measure the reflection and transmission parameters or so-called "S" (scattering) parameters, noise and output power parameters. These measurements are made by applying a microwave signal to an input terminal with a matched impedance on an output terminal and by measuring the coefficent of reflection and the gain in the different possible situations if the component has more than two external access terminals. These measurements are well-known to those versed in the art and are performed by means of equipment comprising a test station with the available space for incorporating a circuit to be measured and two input and output connections which are fixed with respect to the measuring device.
It is therefore necessary to have two microstrip lines matched at 50 ohms for the input and output lines and to have lines for polarization of the component during measurement.
For a given type of measuring equipment, there must be as many packages for supporting the component to be measured as there are different types of components: chips, discrete package and, integrated circuit package, hybrid circuit.
Moreover, since the two input and output microstrip lines are in a fixed position on the measuring equipment, it is necessary to establish for each measurement an electrical connection between the input (or output) microstrip and the particular component terminal which corresponds to the measurement performed, but this terminal is not necessarily in alignment with the microstrip to which it is connected. This results in a length of wire or metallic strip which causes mismatching of the microstrip considered, and, in the most unfavorable case, mismatching is liable to occur both at the input and at the output of the component which is being measured.
Measuring devices of the current types therefore have two access connections formed by a coaxial connector and a microstrip which are fixed and separated by a space which also has fixed dimensions. It is necessary to solder wires or strips in order to counteract the fixed character of the measuring device and to choose the terminals on which the measurement is carried out, thus giving rise to a mismatch of the access connections.